Dr. Christian Kell Consultant in Neurology and Group leader of the Cognitive Neuroscience Group at the Brain Imaging Center, Goethe University Frankfurt, Germany

Although redundancy may exist in neural systems, it is hard to imagine that both hemispheres process stimuli the same way. If this was the case then lateralized brain lesions should not evoke any overt symptoms. Clinical observations suggest that the left hemisphere specialized in producing verbal output while both hemispheres understand speech. This is surprising given that the articulators are represented bilaterally and suggests that the left speech network has an advantage over its contralateral homologue to associate communicative auditory goals with the appropriate motor gestures. My group investigates the sensorimotor interactions underlying overt articulation using fMRI, MEG, and ECog. We hypothesize that phonematic processing in the dorsal auditory stream benefits from rapid and efficient auditory-motor mapping in the left hemisphere. This would privilege the left hemisphere during speech acquisition and by training result in a leftward bias for speech processing. The right hemisphere could contribute in control of prosody given that speech melody-related computations rely on slower temporal scales. In my talk, I will present physiological data in support of this idea but also discuss the consequences of disturbed sensorimotor interactions in developmental stuttering and Parkinson's disease.